A new ferry between North Korea and Russia has docked for the first time at the port of Vladivostok, despite U.S. calls for countries to downgrade relations with Pyongyang over its nuclear and missile-testing programs.

The launch of the first-ever weekly service linking Vladivostok and the North Korean port of Rajin on May 18 was also not deterred by North Korea's test-firing of a ballistic missile on May 14 that landed in the sea near Russia.

The ferry's Russian operator, Investstroytrest, said it was purely a commercial venture that was developed with no subsidies or involvement from Moscow.

Investstroytrest said the ferry will provide transport for North Koreans working in Russia and Chinese tourists wanting to travel by sea to Vladivostok.

China has no ports on the Sea of Japan, while Russia -- especially Vladivostok -- is home to one of the largest overseas communities of North Koreans.

The ferry will also carry Russian tourists going to North Korea, Investstroytrest said, and will provide a faster route for cargo between the two ports, which currently takes 22 days traveling by land routes.

The new service flies in the face of calls by U.S. Secretary of State Rex Tillerson for countries to fully implement United Nations sanctions and go further in an effort to step up pressure on North Korea to give up its weapons programs.

"We call on all nations to fully implement UN Security Council resolutions, and sever or downgrade diplomatic and commercial relations with North Korea," U.S. State Department spokeswoman Katina Adams said on May 18 when asked about the ferry service.

Adams said Russia had an "obligation" under UN Security Council resolutions "to inspect all cargo, including personal luggage, of any individual travelling to or from" North Korea.

Russian Foreign Ministry spokeswoman Maria Zakharova said on May 18 that the new ferry service didn't fall under existing UN sanctions, however.

Japan, whose territorial waters have been violated by some North Korean missile tests, expressed concern about the development.

"In our view, all countries, including Russia, should closely cooperate with the goal of preventing provocations [by Pyongyang] and complying with the UN resolutions," Japanese Chief Cabinet Secretary Yoshihide Suga said.

China, which is North Korea's largest trading partner, has held talks with the United States about stiffening UN sanctions. But Russia has taken a more benign stance toward Pyongyang than other major powers.

Speaking in Beijing this week, Russian President Vladimir Putin said Moscow was against North Korea's nuclear program, but the world should talk to Pyongyang instead of threatening it.